Selection of Top-Like Events in the Lepton+Jets Channels in Early 7 TeV LHC-Data with CMS

The top quark is the heaviest known fermion in the standard model. Due to its large production cross section, pairs of top and antitop quarks will be copiously produced at the Large Hadron Collider (LHC). The event selection deemed for the selection of $t\bar{t}$ events is applied to an early data set of proton-proton collisions at a center-of-mass energy of $7\,\mathrm{TeV}$ corresponding to an integrated luminosity of $0.84\pm 0.09\,\mathrm{pb}^{-1}$. Since this data set is obviously too small to make a statement on the top quark cross section at the LHC, the focus is on the comparison of the predicted background yields and the overall yield of events collected. In addition data-driven techniques to estimate the background contribution from QCD multijet events are evaluated in sideband regions.